1) Field of the Invention
The present invention relates in general to plant cutting apparatus such as grass trimmers, edge trimmers and the like, and aims more particularly at new cutting filaments for such apparatus.
2) Description of Related Art
A cutting filament is usually made by extrusion/drawing of polyamide, and significant advances in these filaments have been known for some years: shapes adapted to reduce noise, improve cutting efficiency, etc., strands made of several materials to improve cutting efficiency, improving biodegradability, reducing cost, etc.
However, all the known filaments are still basically made by the same extrusion/drawing technique in which, at a given stage of the process, or on several occasions, the filament at a temperature at which it has a controlled viscosity is subjected to a longitudinal stretching.
The consequence of this is to give the molecular chains an average orientation extending in the longitudinal direction of the filament, in order to give it a high tensile strength and limit breakages during work.